Bearings are essential components in mechanical systems,with their performance being a key factor influencing the reliability and service life of machinery.Bearing test rigs,as critical equipment for evaluating bearing performance,simulate diverse operating conditions to investigate failure mechanisms and performance characteristics under practical applications.These evaluations offer crucial insights for optimizing bearing design and operational parameters.Specialized working environments,such as heavy-load conditions,deep-sea operations,space applications,and extreme high/low temperatures,impose stringent demands on bearing performance.Consequently,performance assessment and lifespan evaluation of bearings in these conditions have become focal points in the development of advanced bearing test rigs.Research progress of bearing test rigs under heavy load conditions,deep-sea environments,space environments,and high/low-temperature environments are reviewed.The characteristics of bearing test rigs under different environmental simulation technologies are analyzed and an outlook is provided on the research trends in this field,offering a solid foundation for technological advancements in related areas.
High-aspect-ratio microgrooves have been widely applied in various fields,ranging from biology to electronics.However,uniformity is still a technical challenge in the fabrication of high-aspect-ratio microgrooves.Microgrooves with high aspect-ratio and uniformity are fabricated using a 355 nm nanosecond laser by a novel multiple-scan technique.The effects of pulse energy,defocusing amount,and scan number on the depth and width of microgrooves are studied.The results indicate that a slight increase in negative defocusing amount and pulse energy can significantly increase the aspect-ratio,but too large pulse energy will lead to a decrease in uniformity.Therefore,an optimized multiple-scan strategy is proposed to fabricate microgrooves with high aspect-ratio and uniformity by combining multiple processing and defocusing laser irradiations.Microgrooves with an average aspect-ratio as high as 6.84 are achieved,while depth and width uniformity are also significantly improved.The relative standard deviations(RSDs)of depth and width are as low as 4.8%and 4.4%,respectively.Due to the high aspect-ratio and uniformity,the microgrooves are expected to find broad application in fields,such as bio-medical science,3D miniature batteries,and superhydrophobic surface.
碳化硅外延设备是半导体产业链的重要设备之一,外延设备的控制系统直接决定了设备的优劣.针对用户对外延设备控制系统各项功能的需求尚未明确的问题,首先通过会议讨论、问卷调查、专家访谈等方式,收集整理出完整的用户需求清单并分类整合.其次运用改进A-Kano(Analytical Kano)问卷对用户需求及满意度进行权重评分.创新性地对问卷选项分值进行优化设计,有效确保了A-Kano的调查问卷所得到的结果与传统Kano模型没有原则上的偏差,提高了需求划分的相对准确性.进而利用A-Kano模型量化评估外延设备控制系统中各功能的需求层次属性,筛选出基础型需求、期望型需求和魅力型需求.根据需求清单及A-Kano需求实现优先级原则,制定了3 类典型需求的设计、实现与优化研发方案,通过架构设计、应用界面设计、算法优化、差异化需求实现等确保提供给用户稳定的基础型需求、极致的期望型需求和惊喜的魅力需求.最终经实际验证系统稳定、可靠,已生产出膜厚均匀性、掺杂浓度均匀性、表面粗糙度等关键指标符合质量标准的外延片,达到工艺要求,并且用户NPS调研满意度高.
SiC外延设备工作过程中经常会遇到信号干扰的问题,会对生产造成不便,更严重的则会造成设备损毁从而危险人身安全.为此,从工程实践的角度出发,针对控制系统一般性干扰问题和SiC外延设备特殊性干扰问题展开分析.基于目前已有的抗干扰技术,从干扰源、干扰途径入手,系统性地对碳化硅外延设备研发中出现的干扰问题进行分析解决.选取具有特点的通讯干扰、视频信号干扰、模拟信号干扰等干扰问题进行分析;通过RS485 隔离集线器、双绞屏蔽线、接地铜带、抗干扰磁环等,提升设备生产过程中的抗干扰性能;使用示波器、万用表等仪器进行检测.结果表明:采用所提方法能够明显改善信号质量,所提方案稳定、可靠,研究结果为SiC外延设备的研发与工作生产提供参考.
移动机器人的安全运行依赖于可靠的地图构建,现有的同步定位和地图构建(SLAM)方法通常使用相机或者激光雷达构建地图.然而使用单线激光雷达无法检测低于扫描平面的障碍物,使用深度相机虽然能获取三维空间障碍物信息,但由于相机视场过小等限制导致数据中可用信息过少.针对上述单一传感器SLAM方案中存在的缺点.提出一种单线激光雷达与深度相机数据融合的SLAM方法.首先对深度相机数据进行预处理,然后标定出深度相机与激光雷达传感器的外参矩阵,之后利用得到的传感器外参矩阵将深度相机点云数据转换至激光雷达坐标系进行数据融合,最后将融合后的激光雷达扫描数据输入GMapping算法构建二维占据栅格地图.通过搭建Gazebo仿真环境验证所提出的融合方法的可行性与有效性,仿真实验结果表明该方法能够有效融合相机与激光雷达信息,检测地面微小障碍物,建立更加完善的占用栅格地图.
